The invention herein relates to an improved plow structure for use in a sand mulling machine such as is illustrated and described in U.S. Pat. No. Re. 28,659 issued Dec. 23, 1975 to Wenninger, U.S. Pat. No. 3,666,243 issued May 30, 1972 to Bisinella and U.S. Pat. No. 3,256,573 issued June 21, 1966 to Hunter. Such type of mulling apparatus generally consists of a vertically axised bowl having a bottom wall or floor and a peripheral or side wall which is roughly cylindrical in shape. A vertically arranged, central hub located within the bowl is motor driven for rotation.
Vertically axised rollers are mounted upon the hub for rotation with the hub as well as for independent rotation for thereby mulling sand or sand-like material between the rim of the rollers and the interior surface of the peripheral wall of the bowl.
The sand-like material within the bowl is moved about or circulated and also is directed between the respective mulling rollers and bowl wall by means of plows. Such plows typically consist of a radially directed arm portion which sweeps the sand-like material radially outwardly as the arm rotates around the bowl with the hub to which it is connected. In addition, the outer end of the arm is normally provided with a plate which forms a so-called lift plow or main plow which is sloped so that its leading edge tends to scoop up the sand and lift and direct the sand upwardly within the bowl and into the path of the rollers.
The primary purpose of this equipment is to provide a better moldable sand for use in foundry casting of metals. Thus, the equipment mulls or mixes the sand and the binders, where such are used, and reduces lumpiness in the sand. In some foundry uses, the mulled sand may be further processed in a second piece of equipment for additional lump breaking and for aerating and screening the sand.
The invention of this application is concerned with certain improvements to the lift plow which produces an improvement in the mulling or mixing, lump breaking and aerating action of the mulling machine.